Cooking apparatus with thermal energy storage system

Abstract

A thermal energy storage system comprises a heat storage unit having a thermally insulated housing containing a heating core of thermal storage material, such as a plurality of thermal storage bricks. An electric heating element is provided for heating the thermal storage bricks forming the core to a desired temperature. Heat extraction apparatus is provided for extracting thermal energy from the core. The heat extraction apparatus comprises a first air heat exchanger connected to the core to heat air in the first air heat exchanger. An air circulation pipe is connected between the first air heat exchanger and a compartment to be heated, such as an oven. An air circulation fan is mounted in the air circulation pipe between the air heat exchanger and the compartment. A fan controller is operable for controlling operation of the fan to regulate temperature in the compartment.

What is claimed is: 
     
         1 . A cooking apparatus with a thermal energy storage system comprising:
 a heat storage unit having a thermally insulated housing containing a heating core of thermal storage material and an electric heating element for heating the heating core to a desired temperature,   heat extraction apparatus for extracting thermal energy from the heating core,   the heat extraction apparatus comprising an air heat exchanger mounted within the heating core to heat air in the air heat exchanger,   an air circulation pipe connected between the air heat exchanger and an oven compartment to be heated,   an air circulation fan mounted at an outlet of the oven compartment for circulating air through the air circulation pipe between the air heat exchanger and the oven compartment,   wherein the heat exchanger has a housing with an air passageway extending through the heat exchanger housing between an air inlet and an air outlet of the heat exchanger housing, the heat exchanger comprising an upper heat transfer plate and an associated lower heat transfer plate with the heat exchanger housing formed therebetween by side walls extending between the upper heat transfer plate and the lower heat transfer plate, an internal baffle plate which extends between the upper heat transfer plate and the lower heat transfer plate within the heat exchanger housing forming a U-shaped air passageway within the heat exchanger housing between the air inlet and the air outlet of the heat exchanger housing.   
     
     
         2 . The cooking apparatus as claimed in  claim 1 , wherein the heat exchanger housing is a T-shaped housing centrally mounted between the upper heat transfer plate and the lower heat transfer plate leaving a slot at each side of the heat exchanger housing between the heat transfer plates, each slot being filled with the thermal storage material forming the core. 
     
     
         3 . The cooking apparatus as claimed in  claim 1 , wherein the heat exchanger housing has a downwardly stepped air inlet duct at the air inlet and a downwardly stepped air outlet duct at the air outlet of the heat exchanger housing. 
     
     
         4 . The cooking apparatus as claimed in  claim 1 , wherein the air circulation pipe has a feed line for delivering air from the heat exchanger to the compartment and a return line for delivering air from the compartment to the heat exchanger, a bypass valve mounted between the feed line and the return line for bypassing the heat exchanger, the bypass valve having a controller which is operable for blending a quantity of air from the return line with air in the feed line to regulate the temperature of air delivered by the feed line to the compartment. 
     
     
         5 . The cooking apparatus as claimed in  claim 1 , wherein a fan controller is provided for controlling operation of the air circulation fan to regulate the temperature in the compartment. 
     
     
         6 . The cooking apparatus as claimed in  claim 1 , wherein at least one hot plate is mounted on the housing in thermal communication with the core. 
     
     
         7 . The cooking apparatus as claimed in  claim 1 , wherein a water boiler is mounted on the heat storage unit, the water boiler comprising a water heating tank mounted on or within the heating core, the water heating tank having a water inlet for connection to a water supply and an outlet for discharging hot water and steam from the water heating tank.